CREATININE

A creatinine test reveals important information about your kidneys.

Creatinine is a chemical waste product that's produced by your muscle metabolism and to a smaller extent by eating meat. Healthy kidneys filter creatinine and other waste products from your blood. The filtered waste products leave your body in your urine.

If your kidneys aren't functioning properly, an increased level of creatinine may accumulate in your blood. A serum creatinine test measures the level of creatinine in your blood and provides an estimate of how well your kidneys filter (glomerular filtration rate). A creatinine urine test can measure creatinine in your urine.

A serum creatinine test — which measures the level of creatinine in your blood — can indicate whether your kidneys are working properly. How often you need creatinine tests depends on any underlying conditions and your risk of kidney damage.

The amount of creatinine in the blood increases with muscle mass, men usually have higher creatinine levels than women.

Generally, a high serum creatinine level means that your kidneys aren't working well. Your creatinine level may temporarily increase if you're dehydrated, have a low blood volume, eat a large amount of meat or take certain medications. The dietary supplement creatine can have the same effect.

If your serum creatinine level is higher than normal, your doctor may want to confirm the results with another blood or urine test. If kidney damage is a concern, it's important to control any conditions that may be contributing to the damage. It's especially important to manage your blood pressure, which often requires medication. You can't undo permanent kidney damage, but with appropriate treatment you may be able to prevent further damage.